Thin integrated circuit card comprising an improved manually actuated switch

ABSTRACT

A thin integrated circuit card with an improved manually activated switch. The card is of the type that has two external plates, a lower one ( 12 ) and an upper one ( 14 ) that are separated by at least one interconnecting plate in which there is at least one switch ( 26 ). The switch is able to allow or inhibit the passage of an electric current between its two terminals ( 34 ). The switch has a pushbutton ( 28 ) which is positioned at a peripheral edge ( 40 ) of the card.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a thin integrated circuit card having animproved manually actuated switch.

The invention relates in particular to an integrated circuit card of thetype having two external plates, a lower and an upper plate, separatedby at least one intermediate plate, of the type in which the plates haveelectronic components connected to each other by conducting traces, andof the type containing at least one switch able to allow or prohibitpassage of an electric current between two of its terminals that areconnected to at least one of the traces.

Because new manufacturing techniques have been developed, it is nowpossible to obtain very small-sized electronic components that can beintegrated into cards with a very small total thickness.

2. Description of the Related Art

French Patent Application No. 96.12661 has now proposed an integratedcircuit card having both a chip with flush contacts and a circuit forproducing sound signals that is connected to a sound transducer, thewhole being contained in the total thickness of the card which does notexceed 0.8 mm, which is compatible with the widest-spread standardformat for integrated circuit cards.

Such cards, provided with a sound signal producing circuit, can transmitcoded information over a classic telephone line, such informationserving for example for remote control of various types of apparatus.

This information is generally coded by a principle known in English as“dual tone modulation frequency (DTMF).”

However, the presence of such a circuit requires provision of a triggerswitch designed to be actuated by the card user to cause coded signalsto be transmitted.

According to the prior art, such switches are made in the form of adeformable dome provided on one of the external faces of the card, whichthe user must press in the thickness direction of the card to establishan electrical contact between the deformed dome and a conducting areaprovided opposite the dome on one of the faces of the card.

To trigger such a switch, the user must grip the card in its thicknessdirection, for example between the thumb and index finger, and hegenerally applies substantial force to the card which necessarily bendsit, particular in the case of very thin cards.

Such bending, repeated regularly, can eventually damage some of thecomponents of the card, which then becomes unusable.

BRIEF SUMMARY OF THE INVENTION

The goal of the invention is thus to provide a switch for a very thinintegrated circuit card whose design allows easy manipulation by theuser without subjecting the card to excess force.

With this goal, the invention provides an integrated circuit card of thetype seen previously, characterized in that the switch has a pushbuttonprovided at one peripheral edge of the card, which slides in alengthwise direction in the plane of the card between an active and aresting position, and which controls a contact key designed to connectthe terminals of the switch electrically.

According to other characteristics of the invention:

The pushbutton of the switch is guided in a vertical directionperpendicularly to the general plane of card by two faces opposite eachother, an upper face and a lower face, of two plates of the card;

The pushbutton of the switch is received at least partially in a slotformed in at least one of the intermediate plates which terminates in aperipheral edge of the card, and whose two lengthwise edges, oppositeeach other, guide the pushbutton;

The pushbutton of the switch has at least one tab that extends in atransverse direction in the general plane of the card, the tab isreceived in an opening provided in one of the lengthwise edges of slotof the intermediate plate, and the travel of the pushbutton in thelengthwise direction is determined, in at least one direction, bycooperation of the tab with one lengthwise end transverse edge of theopening;

The pushbutton is in the shape of a plate, it has a rear control edge,in it has two lengthwise side edges that guide it in the slot, thepushbutton has two transverse tabs that extend transversely outward fromeach of its lateral edges and are received in two openings formed in thelengthwise edges of the slot, and it has a T-shaped cutout of which alengthwise portion terminates rearward in a transverse portion of thecutout and frontward in a the front edge of the pushbutton;

The pushbutton is returned elastically to its resting position by areturn spring;

The return spring is provided between the front edge of the pushbuttonand a bottom transverse edge of the slot;

The return spring is provided in the form of a deformable elastic bladewhose center portion is supported by the bottom edge of the slot andwhose two edges are bent back so that they contact the front edge of thepushbutton on either side of the front edge of the cutout;

The rear edge controlling the pushbutton is flush with the edge of thecard when the pushbutton is in the resting position, and the outerplates of the card have, opposite the slot, notches formed in theiredges to allow the user to urge the pushbutton lengthwise toward theinside of the card into its active position, particularly by acting onthe pushbutton by one of his fingers;

The contact key is parallelepipedic, it is received in the transverseportion of the cutout of the pushbutton, and one front face of thecontact key is designed to cooperate with a fixed component of theswitch which, when the pushbutton is in the active position, is receivedinside the lengthwise portion of the cutout of the pushbutton;

The fixed component has two ends connected to the terminals of theswitch, which are intended to be connected electrically by the contactkey when the pushbutton is in the active position;

The fixed component is an insulator, both of whose ends are metallizedand which is intended to be short-circuited by the contact key;

The fixed component is a capacitor, and the contact key is designed tocause the capacitor to discharge;

The contact key of the switch is a conducting pellet made of a polymermaterial containing conducting particles;

The switch causes an active component of the card to be triggered;

The switch controls a circuit that produces sound signals;

The thickness of the card is approximately 0.8 mm.

Other characteristics and advantages of the invention will emerge fromreading the detailed description that follows, for understanding ofwhich reference will be made to the attached drawings wherein:

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a perspective exploded schematic view of an integrated circuitcard provided with a switch according to the teachings of the invention;

FIGS. 2 and 3 are partial plane views in which the switch according tothe invention has been illustrated in the resting position and in theactive position.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows an integrated circuit card 10 whose structure isessentially composed of two outer plates, a lower plate 12 and an upperplate 14, separated by an intermediate plate 16.

As can be seen in FIG. 1, upper face 18 of lower plate 12 has electroniccomponents connected together by conducting traces to form, among otherthings, a control circuit for a generator of sound signals supplied to asound transducer 22.

Card 10 can also have other types of components and circuits (not shown)such as a memory module with flush contacts enabling data to beexchanged with an apparatus provided with a suitable reader.

Intermediate plate 16 is critical to the rigidity of the card and hasopenings 24, or windows, designed to accommodate the electroniccomponents when card 10 is assembled.

Lower plate 12 is for example approximately 0.2 mm thick whileintermediate plate 16 can be between 0.4 and 0.5 mm thick, upper plate14 being very thin.

In certain cases, upper plate 14 can also carry electronic components.

It would also be possible to provide several stacked intermediateplates, provided with various windows.

Intermediate card 16 can also have metallized areas (not shown) designedto connect some of the circuits contained in the card with each other.

According to the teaching of the invention, card 10 has a switch 26designed to allow the sound-signal-producing circuit connected to soundtransducer 22 to be triggered.

According to a first feature of the invention, switch 26 is designed tobe mounted between lower plate 12 and upper plate 14 slidably in alengthwise direction in the general plane of card 10.

Switch 26 has an actuating pushbutton 28 provided with a contact key 30that constitutes the trigger element of switch 26 and is designed tocome in contact with a fixed component 32 of switch 26 when pushbutton28 is urged from a shown in FIG. 3, which component 32 is electricallyconnected to two terminals 34 of switch 26, the terminals beingconnected by conducting traces 36 to the control circuit of transducer22.

A return spring 37 is also provided to continuously urge pushbutton 28into its resting position.

Pushbutton 28 is an element also in the shape of a plate, with the samethickness as intermediate plate 16, and is guided lengthwise in a slot38 provided in a rear edge 40 of intermediate plate 16.

Slot 38 has two lengthwise edges 42 that are opposite and parallel toguide pushbutton 28 which is symmetrical with respect to the medianlengthwise axis of symmetry X—X of slot 38.

Slot 38 terminates rearward in rear edge 40 of intermediate plate 16 andis delimited lengthwise frontward by a front transverse edge 44.

Slot 38 can advantageously by made simply and precisely by cutting witha high-pressure water jet or by laser cutting.

When card 10 is assembled, pushbutton 28 is then able to slidelengthwise in slot 38 and is guided, in a direction of the general planeof card 10, by opposite inside faces 18, 46 of lower plate 12 and upperplate 14 is open lengthwise rearward in edge 40 of card 10, and whichclose off slot 38 below and above.

Where several intermediate plates 16 exist, the thickness of pushbutton28 may be such that it does not exceed the thickness of one of theseintermediate plates, and pushbutton 28 is then guided between one ofoutside plates 12, 14 and an intermediate plate that has no guide slot.

Plate-shaped pushbutton 28 has a rear control edge 48 which is flushwith rear edge 40 of intermediate plate 16 when pushbutton 28 is in itsresting position shown in FIG. 2. Moreover, outer plates 12, 14 are eachprovided with a notch 50 opposite the rear end of slot 38 so that theuser can act on rear edge 48 of the pushbutton to urge it lengthwise inthe direction of the inside of the card, toward the bottom of slot 38,up to its active position shown in FIG. 3.

By preventing pushbutton 28 from projecting beyond the side edges of thecard, it is prevented from being inadvertently pushed into its activeposition.

The lengthwise travel of pushbutton 28 in slot 38 is determined by twotabs 52 that extend transversely in the general plane of card 10 fromtwo lengthwise lateral edges 54 of pushbutton 28 which cooperate withthe lengthwise edges 42 of slot 38 to guide pushbutton 28.

Tabs 52 are received in openings 56 cut transversely into lengthwiseedges 42 of slot 38.

Openings 56 are delimited lengthwise by rear transverse edge 58 andfront transverse edge 60 with which tabs 52 cooperate to determine theresting position and active position, respectively, of pushbutton 28.

The travel of pushbutton 28 can for example be approximately 0.5 mm.

Pushbutton 28 is provided with a T-shaped cutout having essentially atransverse part 64 arranged substantially in the center of pushbutton 28and a lengthwise part 68 that extends along axis of symmetry X—X ofswitch 26 and which terminates rearward at transverse portion 64, andfrontward at a front transverse edge 70 of pushbutton 28.

Contact key 30, which is parallelepipedic in shape, is designed to beinserted vertically into transverse portion 64 of cutout 62 in order tohave a front face portion 72 which forms a rear transverse bottom forlengthwise portion 68 of cutout 62.

Key 30 is of substantially the same thickness as pushbutton 28 and asintermediate plate 16 so that it is also held in the directionperpendicular to the general plane of card 10 by outer plates 12, 14with no need for additional fastening means.

Spring 37 that returns pushbutton 28 to its resting position is composedof a deformable blade that has a central portion 74 supported by therear transverse edge 44 of slot 38. Central portion 74 is extended oneach side by arms 76 that are bent rearward lengthwise in the plane ofcard 10 and whose free ends 78, bent back transversely outward relativeto axis of symmetry X—X, rest on front transverse edge 70 of pushbutton28 on outer side of the front lengthwise end of the two lengthwiseportion 68 of cutout 62.

Thus, when pushbutton 28 is urged lengthwise into its active position,arms 76 of pushbutton 28 are elastically bent transversely outward, andwhen the user releases the pressure on rear edge 48, pushbutton 28 isreturned to its resting position.

There are various options for the choice of fixed component 32 of switch26.

Fixed component 32 can for example be a pellet made of a ceramicinsulator, substantially parallelepipedic in shape, whose two transverseend sections 80 are metallized and connected electrically to terminals34 of switch 26.

Fixed component 32 is then joined to upper face 18 of lower plate 12such that, when pushbutton 28 is in the active position, fixed component32 is received in lengthwise portion 68 of cutout 62 of pushbutton 28,and front face 72 of contact key 30 electrically connects the two ends80 of fixed component 32 which has the result of closing an electricalcircuit enabling control circuit 20 to trigger the production of soundsignals.

Switch 26, here of the normally open type, can also be of the normallyclosed type.

Fixed component 32 can also be made in the form of a capacitor with asimilar structure. Current techniques allow capacitors 0.35 mm thick tobe manufactured inexpensively and reliably.

When key 30 comes in contact with fixed component 32, it causes thecapacitor, which had previously been electrically charged, to discharge,causing the difference in voltage at terminals 34 of switch 26 to dropsuddenly, and this signal can be detected by control circuit 20.

In both cases, it is advantageous to use a contact key 30 made in theform of a polymer material containing conducting particles.

Indeed, a “negative” play can be provided between front face 72 ofcontact key 30 and fixed component 32 when pushbutton 28 is in theactive position, namely its front face 72 is slightly in front of a rearface of component 32.

Front face 72 is then able to deform so that, on the one hand, it can bein perfect contact with fixed component 32 in order to provide areliable electrical connection between the two metallized ends 80 offixed component 32 and, on the other hand, to limit the stressestransmitted to fixed component 32 that could tear it off lower plate 12.

Moreover, this enables manufacturing tolerances of such a switch 26 tobe increased to the benefit of the production cost.

Such a design for switch 26 in card 10 enables the forces necessary formanipulating switch 26 to be directed in the general plane of card 10,preventing it from being deformed without its thickness having to beincreased. However, such a switch can also be used in thicker cards,while preserving the benefit of simplicity of production and use.

Of course, such a design for switch 26 can readily be used to controlall types of integrated circuits in a thin card.

Moreover, such a switch is small in size, so that several switches canbe provided on the same card to carry out different functions.

What is claimed is:
 1. Integrated circuit card comprising two externalplates, a lower plate (12) and an upper plate (14), separated by atleast one intermediate plate (16), electronic components connected toeach other by conducting traces (36) on at least one plate, at least oneswitch (26) with two terminals to allow or prohibit passage of anelectric current between the two terminals (34) that are connected to atleast one of the traces (36), pushbutton (28) provided at one peripheraledge (40) of the card (10), which slides in a lengthwise direction inthe plane of the card between an active and a resting position, andwhich controls a contact key (34) designed to connect the terminals (34)of switch (26) electrically, the pushbutton (28) of switch (26) beingslidable mounted in a slot (38) formed in at least one of theintermediate plates (16), which terminates in the peripheral edge (40)of card (10), and whose two lengthwise edges (42), opposite each other,guide pushbutton (28).
 2. Integrated circuit card according to claim 1wherein said pushbutton (28) in the resting position, has its outerperipheral flush with or slightly inside the edge (40) of the card (10).3. An integrated circuit card comprising two external plates, a lowerplate (12) and an upper plate (14), separated by at least oneintermediate plate (16), at least one of the plates having electroniccomponents thereon connected to each other by conducting traces (36), atleast one manually operable switch (26) having a normal resting positionand an activated position for controlling passage of an electric currentbetween two terminals (34) connected to at least one of the traces (36),said switch (26) has a manual operated pushbutton (28) located at oneperipheral edge (40) of the card (10), said pushbutton being movablefrom the normal position at the edge inwardly towards an interior ofsaid card sliding in a direction parallel to a major plane of the card,and a contact key (30) controlled by said pushbutton and movable in thesame direction as said pushbutton, and when in said activated positionsaid key connects the terminals (34) of the switch (26) electrically. 4.Integrated circuit card according to claim 3 wherein pushbutton (28) ofswitch (26) is guided in a direction parallel to the general plane ofcard (10) by two faces opposite each other, an upper face (18) and alower face (46), respectively, of said two plates (12, 14) of card (10).5. Integrated circuit card according to claim 3 wherein the pushbutton(28) of switch (26) moves at least partially in a slot (38) formed in atleast one of the intermediate plates (16), which terminates at theperipheral edge (40) of card (10), and having two lengthwise edges (42),opposite each other, for guiding said pushbutton (28) in said slot. 6.Integrated circuit card according to claim 5, wherein said pushbutton(28) of switch (26) has at least one tab (52) that extends in atransverse direction in the general plane of card 910), said tab (52)being received in an opening (56) provided in one lengthwise edge (42)of slot (38) of intermediate plate (16), whereby the travel ofpushbutton (28) in the lengthwise direction is determined, in at leastone direction, by cooperation of tab (52) with one lengthwise end oftransverse edge (58, 60) of opening (54).
 7. Integrated circuit cardaccording to claim 6, wherein pushbutton (28) is in the shape of a platewith a rear control edge (48) and two lengthwise side edges (54) thatguide said pushbutton in slot (38), said pushbutton (28) has twotransverse tabs (52) that extend transversely outward from each of itslateral edges (54) and are received in two openings (56) formed inlengthwise edges (42) of slot (38), and said pushbutton has a T-shapedcutout (62) of which a lengthwise portion (68) terminates rearward in atransverse portion (64) of the cutout and frontward in a front edge (70)of pushbutton (28).
 8. Integrated circuit card according to claim 7further comprising a return spring (37) provided between the front edge(70) of pushbutton (28) and a bottom transverse edge (44) of slot (38).9. Integrated circuit card according to claim 8, wherein the returnspring (37) is a deformable elastic blade having a center portion (74)supported by bottom edge (44) of slot (38) and two edges (76) being bentback so that they contact front edge (70) of pushbutton (28) on eitherside of the front edge (68) of the cutout (62).
 10. Integrated circuitcard according to claim 7 wherein rear edge (48) controlling pushbutton(28) is flush with edge (40) of card 910) when pushbutton (28) is in theresting position, and the outer plates (12, 14) of card (10) have,positioned opposite slot (38), notches (50) formed in their edges (40)to allow a user to urge pushbutton (28) lengthwise into its activeposition toward the inside of card (10), whereby activating the switchby acting on pushbutton (28) by one of the users fingers.
 11. Integratedcircuit card according to claim 7 wherein contact key (30) isparallelpipedic shaped and moves with the transverse portion (64) ofcutout (62) of pushbutton (28), and one front face (72) of contact key(30) being designed to cooperate with a fixed component (32) of switch(26) which, when pushbutton (28) is in the active position, is insidethe lengthwise portion (68) of cutout (62) of pushbutton (28). 12.Integrated circuit card according to claim 11, wherein fixed component(32) has two ends (80) connected to terminals (34) of switch (26), whichare connected electrically by contact key (30) when pushbutton (28) isin the active position.
 13. Integrated circuit card according to claim12, wherein the fixed component (32) is an insulator, whose ends (80)are metallized and which is short-circuited by contact key (30) in theactive position.
 14. Integrated circuit card according to claim 3wherein the pushbutton (28) is returned elastically to its restingposition by return spring (37).
 15. Integrated circuit card according toclaim 3, wherein fixed component (32) is a capacitor, and contact keywhen in the active position (30) causes the capacitor to discharge. 16.Integrated circuit card according to claim 3, wherein contact key (30)of switch (26) is a conducting pellet made of a polymer material chargedwith conducting particles.
 17. Integrated circuit card according toclaim 3, wherein switch (26) when in the active position causes anactive component (20, 22) of card (10) to be triggered.
 18. Integratedcircuit card according to claim 17, wherein switch (26) controls acircuit (20) producing sound signals.
 19. Integrated circuit cardaccording to claim 3, wherein the thickness of card (10) isapproximately 0.8 mm.